code: def __call__(self, x):
      if self.cover_all is not None:
          return self.ops(*([x] + self.args), cover_all=self.cover_all)
      else:
          return self.ops(*([x] + self.args))
  
file_path: chainer/tests/onnx_chainer_tests/functions_tests/test_poolings.py
imports: import chainer
  import chainer.functions
  from chainer import testing
  import numpy
  from onnx_chainer.testing import input_generator
  from onnx_chainer_tests.helper import ONNXModelTest
label_desc: Use image node_id 2 for calling the Model obj's underlying member method code with example usage: obj.__call__(x) and returns: self, self